Answer: The correct option is D (Powders have more surface area and will dissolve faster).
Step-by-step explanation:
For a scientist to investigate whether a powered pill will dissolve faster than a solid pill is putting the rate of the reaction under study.
Rate has to do with what is achieved per unit time. One of the factors affecting rates of chemical reaction includes the SURFACE AREA.
Reagents in solution tend to react faster than reagents in solid form. This is because molecules are freer to move about and collide more effectively in solutions. For solids, the more the surface area exposed for reaction the faster the reaction. For example, a lump of Zinc will not react as fast as powdered zinc with dilute hydrochloric acid to produce hydrogen.
Therefore, with the above explanation and example concerning surface area in a chemical reaction, the hypothesis the scientist should develop is that powers which has more surface area will dissolve faster than the soils pills.